The present disclosure relates generally to gossamer apparatus and systems for use with spacecraft to increase a surface area (e.g., to form a drag surface defining the suface area) of the spacecraft and/or to decelerate a spacecraft, e.g., to modify the spacecraft's orbit, to de-orbit the spacecraft, for aerobraking the spacecraft, to lower the apogee of the orbit of the spacecraft, for providing a solar sail, etc.
An increasing number of spacecraft are located in low earth orbit. With spacecraft fragmentation, a growing population of orbital debris has been created. Spacecraft may be de-orbited at the end of their operational lives to lower the amount orbital debris. Various standards may require spacecraft to de-orbit within 25 years of the end of their operational life. Traditionally, chemical propulsion systems have been used to de-orbit spacecraft from low-earth orbit at the end of their operational life.
To reduce propellant requirements on spacecraft entering orbit around a planetary body with an atmosphere such as, e.g., Earth, Mars, etc., an “aerobraking” approach may be used. “Aerobraking” reduces the velocity of the spacecraft when initially arriving at a planetary body by using drag created by the atmosphere of the planetary body to reduce the eccentricity of the orbit (e.g. to change the orbit from a hyperbolic to an elliptical trajectory, or to circularize the orbit). In other words, a spacecraft may use aerobraking to reduce the velocity of the spacecraft. For example, the surface area of appendages already used by the spacecraft such as, e.g., solar arrays, etc., may be used for aerobraking.
Some space missions may require a spacecraft to lower its orbit without fully de-orbiting the spacecraft, e.g., reducing apogee to circularize an orbit. Traditionally, chemical propulsion systems may be used for orbit transfers such as, e.g., a partial Hohmann transfer.
Spacecraft may currently deorbit from low Earth orbit using chemical propulsion, electro-dynamic drag, electric propulsion, and natural orbit decay. Chemical propulsion systems are expensive and heavy, and must be integrated into the spacecraft design from conception. In addition, not all satellites require station keeping, orbital maneuvering, or propulsion based attitude control, and therefore, a need for a propulsion system apart from for de-orbiting may not exist. Propulsion systems are often high cost, and thus may represent a large investment for a part of the mission that does not directly contribute to operations.
Electro-dynamic tethers have been developed to de-orbit spacecraft. Electro-dynamic tethers may, however, require complex deployment and may have reliability issues. Further, each of chemical propulsion, electro-dynamic drag, and electric propulsion systems may require functions of the spacecraft systems to be operational at end of life. If the spacecraft systems fail during operations (e.g., prior to de-orbit), then de-orbit may not be able to be accomplished.
Natural orbit decay from atmospheric drag has also been used to de-orbit spacecraft, but the rate of decay is proportional to the surface area of the spacecraft. Most spacecraft in appreciably high orbits (e.g., about 600 kilometers to about 1000 kilometers) may not have a large enough surface area to produce sufficient drag to de-orbit the spacecraft within a 25 year period.